How to disable app syncing without removing all apps and their data from iOS device?

What always bugged me, before iOS 5, was that I had to sync all those apps installed on my iPhone and iPad to my Mac, for various reasons: it takes away space (around 20GB, which is a lot on a small MacBook Air SSD), everytime an app gets updated, it had to be transferred again, and you can't use those apps on the Mac anyway. But I did it, so I had a backup of the app data.

Now with iOS 5 and backup to iCloud, all app data is being saved to iCloud. There's no need to keep syncing apps to my Mac.

So I tried disabling app syncing in iTunes, but there's no option to stop syncing but leave all the apps installed on the iOS device. It's either keep syncing, or stop syncing and lose all your apps, and, more importantly, all app data. If it was only the apps themselves, I could download them again, but the deletion of app data is the real killer.

Is there a way to do that? Would it work if I stopped app syncing and then restored the iOS device from an iCloud backup? Would I get to keep the app data?

You can delete the apps from the computer (the actual .app files) but keep them in iTunes and it will keep syncing app data just fine, as long as the app is still present on the phone. I'm doing this myself.

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Or an alternative might be to backup your phone to iCloud, and then disable app sync in iTunes, thus deleting all data on the phone, and then restoring the phone from iCloud? I haven't tried this, but it could work. Or it just reenables the sync, i'm not sure... worth a try?